Risks and benefits of anticancer drugs in advanced cancer patients: A systematic review and meta-analysis

Background: Randomized clinical trials (RCTs) of anticancer drugs without active comparators in patients who have exhausted standard of care treatment options are debated. We aimed to quantify the safety and the efficacy of anticancer drugs in advanced cancer patients who have exhausted standard of care treatments from RCTs without active comparators. Methods: This systematic review and meta-analysis was conducted according to preferred reporting Items for systematic review and Meta-Analyses (PRISMA) guidelines (CRD42021243968). A systematic literature search of English language publications from January 1, 2000, to January 7, 2021, was performed using MEDLINE (PubMed). Eligible trials included all RCTs evaluating anticancer drugs in adult patients with advanced solid tumors with a control arm without any anticancer drug consisting of best supportive care with or without a placebo. RCTs performed in the adjuvant, neoadjuvant or maintenance settings were excluded, as were clinical trials evaluating anticancer drugs in combination with radiotherapy. Two authors (C.M.B. and E.C.) independently reviewed the studies for inclusion. Data from published reports were extracted by investigators, and random-effects meta-analysis was performed to estimate the overall hazard ratios (HRs) of progression-free survival (PFS) and overall survival (OS). Correlations between severe toxicity and efficacy was assessed using R(2) measures. Findings: Of 3551 studies screened, 128 eligible trials were found involving 47,432 patients. The HRs for PFS and OS were 0·58 [95%CI: 0·53–0·63] and 0·82 [95%CI: 0·78–0·85]. The absolute benefits however were limited with PFS and OS gains of 2·1 and 0·5 months. The absolute excesses in all grade, severe grade III, IV and V (death) adverse events between the two arms were +13·9%, 10·2%, and +0·5%. A weak correlation was measured between the excess of severe toxicity and efficacy (all R² < 0·2). Interpretation: Anticancer drugs evaluated in RCTs against no active treatment benefited trial participants. Severe toxicity did not significantly correlate with efficacy. FUNDING: None.